Oxidative metabolism, as indicated by the fluorescence of NADH and oxgyen consumption, is being assessed to investigate potassium ion kinetics in the cat brain. Research is being conducted to determine if the potassium clearance process after activation of the cortex is active or passive. Investigations are also being conducted to determine the applicability of the NADH fluorescence technique to exposed myocardium. BIBLIOGRAPHIC REFERENCES: Schuette, W.H., O'Connor, M., Lewis, D.V. and Van Buren, J.M.: The Design and Operation of a Dual Beam Long Focal Length Fluorometer for Monitoring the Oxidative Metabolism In Vivo. Med. Biol. Engr., March, 235, 238, 1976. Schuette, W., Vern, B. and Whitehouse, W.: A Television Fluorometer for Evaluating Oxidative Metabolism of Exposed Myocardium In Vivo. In proceedings of the Association for Advancement of Medical Instrumentation 12th Annual Meeting, San Francisco, March 13-17, 1977, p. 50.